subplot(2,2,1)spectrogram(signal1_L,hann(1024),512,nfft1,FS,'yaxis');title('Original left signal');subplot(2,2,3)spectrogram(signal2_L,hann(1024),512,nfft1,FS,'yaxis');title('Modified left signal');subplot(2,2,2)spectrogram(signal1_R,hann(1024),512,nfft1,FS,'yaxis');title('Original right signal');subplot(2,2,4)spectrogram(signal2_R,hann(1024),512,nfft1,FS,'yaxis');title('Modified right signal');